The European champions emerged triumphant from the first part of their double header with the Turks to maintain their 100% record in the qualifiers and move six points clear of second-placed Bosnia-Herzegovina at the top of Group Five.

The result extended Spain's unbeaten run to 30 matches - of which 28 have ended in victory - and Casillas has urged his team-mates to continue in that vein in order to book their ticket to South Africa as soon as possible.

"It is probably the most important game we have left," he said. "Because to get the three points is to put a foot in the World Cup in South Africa.

"We already won a difficult game the other day and we are where we want to be, because we were counting on winning at home and not losing there, so if we come away with victory we can leave qualification on the right track.

"We don't give a lot of importance to records, because even though the whole world likes facts and history, here what's important is to win the games and to get closer to qualification."

Victory in Istanbul would almost certainly see Spain through to the World Cup finals but they only triumphed by the slenderest of margins at the Bernabeu and know they are in for a tricky test tomorrow.

Their performance on Saturday saw them come in for some criticism but coach Vicente Del Bosque has defended his players.

"There was the idea that Spain had played a bad game but it doesn't seem as if we played so bad," he said.

"For sure they played well in the first half and stopped us from playing our football but in the second we were consistent defensively and pushed forward in attack.

"We have to be careful in keeping our privileged position in the group, we'll go there remembering that Bosnia and Turkey are also there."

Del Bosque has a fully-fit squad to choose from but has admitted he will rest some players, bringing in others who are fresher, and in all likelihood will use a formation with just one striker - set to be Liverpool's Fernando Torres.

Spain might be on a seemingly inexorable march to the World Cup finals but defeat in Istanbul would blow Group Five wide open again.

Turkey striker Nihat Kahveci insists victory is more than possible and hopes the notoriously passionate home support will play their part.

"Beating Spain is not a dream," he said.

"We shouldn't forget that we are playing against the best national team in the world, but the Turkish team have been able to play with their own style which is always going out to win.

"I think that our successes and our failures have been exaggerated. If I score a goal I am a national hero; if I don't score, a traitor to my country.

"The atmosphere will be impressive but not an inferno in the bad sense of the word, but in the good."